Dissertations / Theses on the topic 'Functional Continuous Flow Reactors'

Garlic secondary metabolites are organosulfur compounds that possess prophylactic properties. The chemical composition of garlic oil extracts consists of a combination of these compounds. The instability of a major component, allicin 5, limits the commercial viability of garlic oil extracts. The synthesis of garlics organosulfur compounds has been performed in batch reactors. In this thesis, flow reactors were utilised to improve the throughput, reduce the operating conditions. The thermolysis of allicin 5 is the solitary approach to produce the garlic metabolite, ajoene 14. Ajoene 14 has greater stability compared to allicin 5 that possesses interesting biological activity. The primary three-step synthesis investigated consisted of dialkyl polysulfide synthesis, subsequent oxidation and finally the terminal thermolysis. In addition, other garlic metabolites have also been produced. The synthesis of unsymmetrical monosulfides and their subsequent oxidation was investigated using novel heterogeneous packed-bed flow reactors. The stable amino acid, alliin 15, is the precursor of allicin 5. Alliin 15 was also synthesised in homogeneous flow mode. The telescoped synthesis of alliin 15 was successfully completed using a semi-batch reactor. Development of novel approaches to synthesise garlics organosulfur compounds is reported in this thesis. Finally, the flow reactor systems, experimental details and characterisation of the compounds are described.

Palladium complexes have the ability to catalyse cross-coupling of two organic moieties through the formation of transient metal-carbon bonds, thus bringing them closer to each other to facilitate the formation of a new bond. Palladium-catalysed coupling reactions are one of the most important carbon-carbon forming reactions available to organic chemists and many of these reactions rely on the reactivity of aryl-palladium complexes. The investigation of new aryl-palladium precursors is thus of great interest, especially as more sustainable and economic methods can be developed. This thesis describes the use of carboxylic acids and sodium arylsulfinates as such new arylating agents. Protocols for microwave-assisted palladium(II)-catalysed decarboxylative synthesis of electron-rich styrenes and 1,1-diarylethenes were developed. However, these transformations had very limited substrate scopes which prompted the investigation of sodium arylsulfinates as alternative arylating agents. These substrates were employed in the microwave-assisted palladium(II)-catalysed desulfitative addition to nitriles, and the substrate scope was demonstrated by combining a wide array of sodium arylsulfinates and nitriles to yield the corresponding aryl ketones. The application of the desulfitative reaction in a continuous flow setup was demonstrated, and aluminium oxide was identified as safe alternative to borosilicate glass as a reactor material. The mechanisms of the decarboxylative and desulfitative transformations were investigated by density functional theory (DFT) calculations. The desulfitative reaction was also investigated by direct electrospray ionization mass spectrometry (ESI-MS), providing further mechanistic insight. Finally, a protocol for the safe and convenient synthesis of a wide range of sodium arylsulfinates was developed.

The polymerase chain reaction (PCR) is an enzyme catalyzed technique, used to amplify the number of copies of a specific region of DNA. This technique can be used to identify, with high-probability, disease-causing viruses and/or bacteria, the identity of a deceased person, or a criminal suspect. Even though PCR has had a tremendous impact in clinical diagnostics, medical sciences and forensics, the technique presents several drawbacks. For example, the costs associated with each reaction are high and the reaction is prone to contamination due to its inherent efficiency and high sensitivity. By employing microfluidic systems to perform PCR these advantages can be circumvented. This thesis addresses implementation issues that adversely affect PCR in microdevices and aims to improve the efficiency of the reaction by introducing novel materials and methods to existing protocols. Molecule-surface-interactions and temperature control/determination are the main focus within this work. Microchannels and microreactors are characterized by extremely high surface-to-volume ratios. This dictates that surfaces play a dominant role in defining the efficiency of PCR (and other synthetic processes) through increased molecule-surface interactions. In a multicomponent reaction system where the concentration of several components needs to be maintained the situation is particularly complicated. For example, inhibition of PCR is commonly observed due to polymerase adsorption on channel walls. Within this work a number of different surface treatments have been investigated with a view to minimizing adsorption effects on microfluidic channels. In addition, novel studies introducing the use of superhydrophobic coatings on microfluidic channels are presented. Specifically superhydrophobic surfaces exhibiting contact angles in excess of 1500 have been created by growing copper oxide and zinc oxide nanoneedles and silica-sol gel micropores on microfluidic channels. Such surfaces utilize additional surface roughness to promote hydrophobicity. Aqueous solutions in contact with superhydrophobic surfaces are suspended by bridging-type wetting, and therefore the fraction of the surface in contact with the aqueous layer is significantly lower than for a flat surface. An additional difficulty associated with PCR on microscale is the detennination and control of temperature. When perfonning PCR, the ability to accurately control system temperatures is especially important since both primer annealing to single-stranded DNA and the catalytic extension of this primer to form the complementary strand will only proceed in an efficient manner within relatively narrow temperature ranges. It is therefore imperative to be able to accurately monitor the temperature distributions in such microfluidic channels. In this thesis, fluorescence lifetime imaging (FLIM) is used as a novel method to directly quantify temperature within microchannel environments. The approach, which includes the use of multiphoton excitation to achieve optical sectioning, allows for high spatial and temporal resolution, operates over a wide temperature range and can be used to rapidly quantify local temperatures with high precision.

One of the most important boron minerals, colemanite is reacted with sulfuric acid to produce boric acid. During this reaction, gypsum (calcium sulfate dihydrate) is formed as a byproduct. In this study, the boric acid production was handled both in a batch and four continuously stirred slurry reactors (4-CFSSR&rsquo
s) in series system. In this reaction system there are at least three phases, one liquid and two solid phases (colemanite and gypsum). In a batch reactor all the phases have the same operating time (residence time), whereas in a continuous reactor all the phases may have different residence time distributions. The residence time of both the reactant and the product solids are very important because they affect the dissolution conversion of colemanite and the growth of gypsum crystals. The main aim of this study was to investigate the dynamic behavior of continuous flow stirred slurry reactors. By obtaining the residence time distribution of the solid and liquid components, the non-idealities in the reactors can be found. The experiments performed in the continuous flow stirred slurry reactors showed that the reactors to be used during the boric acid production experiments approached an ideal CSTR in the range of the stirring rate (500-750 rpm) studied. The steady state performance of the continuous flow stirred slurry reactors (CFSSR&rsquo
s) in series was also studied. During the studies, two colemanites having the same origin but different compositions and particle sizes were used. The boric acid production reaction consists of two simultaneous reactions, dissolution of colemanite and crystallization of gypsum. The dissolution of colemanite and the gypsum formation was followed from the boric acid and calcium ion concentrations, respectively. The effect of initial CaO/ SO42- molar ratio (1.00, 1.37 and 2.17) on the boric acid and calcium ion concentrations were searched. Also, at these initial molar ratios the colemanite feed rate was varied (5, 7.5, 10 and 15 g/min) to change the residence time of the slurry. Purity of the boric acid solution was examined in terms of the selected impurities, which were the magnesium and sulfate ion concentrations. The concentrations of them were compared at the initial molar ratios of 1.00 and 1.37 with varying colemanite feed rates. It was seen that at high initial CaO/ SO42- molar ratios the sulfate and magnesium ion concentrations decreased but the calcium ion concentration increased. The gypsum crystals formed in the reaction are in the shape of thin needles. These crystals, mixed with the insolubles coming from the mineral, are removed from the boric acid slurry by filtration. Filtration of gypsum crystals has an important role in boric acid production reaction because it affects the efficiency, purity and crystallization of boric acid. These crystals must grow to an appropriate size in the reactor. The growth process of gypsum crystals should be synchronized with the dissolution reaction. The effect of solid hold-up (0.04&ndash
0.09), defined as the volume of solid to the total volume, on the residence time of gypsum crystals was investigated and the change of the residence time (17-60 min) on the growth of the gypsum was searched. The residence time at each reactor was kept constant in each experiment as the volumes of the reactors were equal. The growth of gypsum was examined by a laser diffraction particle size analyzer and the volume weighted mean diameters of the gypsum crystals were obtained. The views of the crystals were taken under a light microscope. It was observed that the high residence time had a positive effect on the growth of gypsum crystals. The crystals had volume weighted mean diameters of even 240 µ
m. The gypsum crystal growth model was obtained by using the second order crystallization reaction rate equation. The residence time of the continuous reactors are used together with the gypsum growth model to simulate the continuous boric acid reactors with macrofluid and microfluid models. The selected residence times (20-240 min) were modeled for different number of CSTR&rsquo
s (1-8) and the PFR. The simulated models were, then verified with the experimental data. The experimentally found calcium ion concentrations checked with the concentrations found from the microfluid model. It was also calculated that the experimental data fitted the microfluid model with a deviation of 4-7%.

The rapidly increasing prices of petroleum fuels and potential shortages, have created a need for renewable fuels derived from organic waste products. The objective of this research project is to produce advanced multipurpose, continuous microwave biofuelslchemical reactors to utilise waste vegetable oils. The heat transfer efficiency of the reactor was studied using pure vegetable oils to establish the reactor design, operating temperatures and controls necessary to produce First Generation biodiesel by advanced microwave technology. Water modelling was used to scale up the reactors from 200 W to 1.2 kW and then subsequently to 2 kW. Once the initial continuous reactor was optimised, the work was repeated using various grades of waste cooking oils provided by Longma Clean Energy Ltd. In order to achieve the required conversion to give 96.5% methyl esters, these oils needed larger quantities of both catalyst and methanol to reduce the viscosity of the crude oil. The system was then modified to carry out microwave assisted methanol extraction of free fatty acids, with the addition of a decanter to allow continuous phase separation. This process produced no glycerol, was energy efficient and the free fatty acids that were removed, were recovered in the methanol distillation unit. In the future, the waste frictional heat from the diesel engine could be used to grow algae, the waste heat from the exhaust gases could be used to heat the distillation unit and the carbon dioxide could be biofixated by microalgae. An industrial prototype 1.2 kW microwave de-acidification unit has now been built at the Longma Clean Energy site at Hereford. There is a surplus of poor quality biodiesel glycerol that is currently regarded as a waste product. The novel continuous microwave unit which was developed from the biodiesel reactor has been used to acetyl ate the glycerol with acetone at below 50°C to produce acetals for use as fuel additives. An atmospheric/vacuum fractional distillation column will be required to recover the methanol or acetone and to distil the acetal from the unreacted glycerol, which is then recycled. The technology developed can utilise any waste cooking oils, acidic seed oils or fats as biofuels for combined heat and power generation or to convert them to biodiesel fuels. This research work is the basis of an integrated, green, low carbon, microwave based refinery. 2

This study has developed a new empirical substrate removal model for continuous flow stirred tank reactor (CFSTR) and sequencing batch reactor (SBR) systems. In this model, an exponential function of volatile suspended solids (VSS) was introduced to express active biomass in substrate utilization kinetics. The proposed empirical substrate removal model is expressed as: dS/dt = $\rm -K\sp\prime X\sb{v}\sp{n}S.$ The kinetic constants K$\sp\prime$ and n in the model were estimated from batch tests. Then, this model was validated for CFSTR and SBR continuous flow systems. The results obtained from batch tests, conducted with sludge from the CFSTR and SBR systems, showed that the exponential model can more accurately express the substrate removal rate in a batch reactor than the conventional first order equation. A comparison of the new exponential and the first order model indicates that the exponential model can more accurately predict the effluent COD concentrations for both CFSTR and SBR continuous flow systems. The first order rate constants (K) for both CFSTR and SBR systems were affected by the reactor sludge age, the influent COD and the biomass concentrations. The kinetic constants K, yield factor (Y), and endogenous decay coefficient $\rm (k\sb{d})$ obtained for SBR system were higher than those for CFSTR. The statistical analysis results indicated that SBR system performed at a higher substrate removal efficiency compared to the CFSTR. Also the sludge grown in the SBR reactors had a better settleability than that produced in the CFSTR. The optimal organic loadings for controlling sludge bulking in the CFSTR and SBR were found to be less than 0.7 mg COD/mg VSS/d and 1.2 mg COD/mg VSS/d, respectively. In addition, the SBR reactor could be operated at an F/M ratio of 1.4 mg COD/mg VSS/d, which was twice the F/M ratio in the CFSTR without a significant decrease in treatment efficiency.

Le furfural, identifié comme l'un des 30 principaux produits chimiques biologiques, est une molécule importante en terme de chimie verte et développement durable. L'objectif de ce travail de doctorat est de réaliser la synthèse et la conversion du furfural en flux continu et par lots. Ici, nous avons développé des méthodes plus éco-efficiente pour la synthèse du furfural, et valorisé le furfural en produits à haute valeur ajoutée, tels que le 2-furonitrile, l'alcool furfurylique, etc... Plusieurs questions clés ont été identifiées afin de concevoir des processus plus écologiques que les processus actuels. En détail, des expériences de synthèse du furfural ont été réalisées dans l'eau pure ou dans un mélange eau-solvants organiques lorsque des co-solvants (verts ou écologiques) sont nécessaires. L'irradiation par micro-ondes a été choisie comme méthode de chauffage pour accélérer le processus de déshydratation, et un réacteur à flux continu à micro-ondes a également été utilisé pour améliorer la productivité du furfural. En partant du furfural pour produire des produits chimiques à haute valeur ajoutée, des réacteurs à flux efficace, tels que Pheonix, H-cube Pro ainsi que des micro-ondes à flux continu avec micro-réacteur, ont également été identifiés comme des alternatives intéressantes pour améliorer la productivité des composés cibles. En conséquence, certains résultats prometteurs ont été obtenus du point de vue de l'industrie
Furfural, which has been identified as one of top 30 bio-based chemicals, is an important green platform molecule, The aim of this PhD work is to realize the synthesis and conversion of furfural in batch and continuous flow. Here, we developed sorne greener methods for furfural synthesis, and valorized furfural into high value-added products, such as 2-furonitrile, furfuryl alcohol etc. Several keys issues were identified in order to design processes greener than the current ones. ln detail, experiments for furfural synthesis were performed in water or in water and organic solvent when co-solvents (green or eco-friendly) are necessary. Microwave irradiation has been chosen as the heating method to accelerate the dehydration process, and microwave continuous flow reactor was also applied to improve furfural productivity. When starting from furfural to produce high value-added chemicals, efficient flow reactors, suc as Pheonix, H-cube Pro as well as microwave continuous flow With micro-reactor, were also identified as interesting alternatives to improve the productivities of target compounds. As a result, some promising results were obtained in the viewpoint of industry

The prevalence of chiral amines in pharmaceutical compounds means that efficient synthetic methods are highly desirable. Asymmetric catalysis offers the opportunity for enantioselective synthesis of chiral amines under milder reaction conditions. Chemical and biological catalysts both offer specific advantages and disadvantages that are different to the other catalyst type. Therefore, the combination of catalysts would allow for the advantages of each to be exploited, whilst overcoming the associated disadvantages. This research investigates the combination of chemical and biological catalysts for the production of chiral amines and essential medicines using continuous reactors. Continuous reactors are increasingly seen as a method to improve synthesis routes due to their improved productivity and safety compared to batch reactors. In addition to continuous reactors, immobilised catalysts and design of experiments (DoE) strategies were employed for the development of optimised procedures. Firstly, the enzymatic kinetic resolution of a chiral primary amine was studied in a continuous packed bed reactor (PBR) using an immobilised lipase enzyme. Optimum reaction conditions were determined using a one variable at a time (OVAT) approach to give the maximum 50% conversion with high product ee in only a 6 min residence time (tRes). The PBR system was then applied to an expanded substrate set, including chiral amines and alcohols, to act as a comparison to the standard amine. Secondly, metal catalysed racemisation was investigated as a method to utilise the waste enantiomer from the enzymatic resolution in a dynamic kinetic resolution process (DKR). Homogeneous and heterogeneous Ir, Ru and Pd catalysts were tested for the amine racemisation step. However, the amount of racemisation observed was not sufficient and uncontrolled dimerisation primarily occurred. Next, the enzymatic PBR was applied to the production of essential medicines via enzymatic ammoniolysis. The development of cheaper more efficient methods to produce essential medicines is vital to make them more affordable and accessible to the developing world. In this instance, the reaction conditions were optimised using DoE with the objective being to maximise conversion. Nicotinamide and pyrazinamide were produced in 94% and 100% yields with a tRes of 60 min and 20 min, respectively. The ammoniolysis of a chiral substrate was also tested; however, this was not successful using the experimental conditions described. Finally, metal catalysed N-alkylation using Ir was investigated for the N-alkylation of the chiral primary amine as an alternative method to utilise the waste enantiomer from the continuous resolution. DoE and microwave heating techniques were employed to optimise the reaction conditions and reduce the amount of waste associated with development. In this example, the formation of un-desired dimeric products was problematic and so the optimisation objectives were both maximum conversion and maximum selectivity for the desired product. Overall, the transferal of processes into continuous PBR and optimisation techniques allowed for the intensification of reaction conditions, which led to more productive, efficient routes. However, the difficulties in combining chemical and biological catalysts were also highlighted when the combination of reactions was attempted.

Due to their small particle size, nanoparticles ( < 100 nm in diameter) have an increased surface area to volume ratio compared to larger particles, meaning that surface attributes become increasingly important over bulk properties. Chemically, this means more atoms in the material have unsatisfied coordination environments compared to atoms in the bulk of the particle. In many cases, this leads to materials with significantly different bulk properties compared to much larger particles; some of these unique properties are desirable in high technology applications such as sun screens, catalysts, etc. This thesis explores the use of Continuous Hydrothermal Flow Synthesis (CHFS) reactors as a niche technology to controllably produce nanoparticles at different process scales. In CHFS, a metal ion feed is mixed with superheated water (the latter is typically above the critical temperature and pressure of water, i.e. 374 °C, 22.1 MPa), and nanoparticles are precipitated. This thesis presents data relevant to an evaluation of a laboratory scale CHFS process (able to produce ca. 100 g a day of nanoparticles). This included the development of a new type of mixer for this type of process suitable for the continuous precipitation of nanoparticles. The knowledge gained from in situ measurements and particle property measurements was then applied to the successful scale up of the technology to produce up to ca. 2 kg per hour of nanoparticles. It was demonstrated that the versatility of a flow process and the rapid crystallising environment in a CHFS system could be effectively exploited for the production of target nanoparticles when appropriate synthesis conditions were used. This thesis has also demonstrated the versatility of CHFS in that as formed particles could be surface functionalised in flow by use of an additional feed in process. The outcomes of this thesis have been demonstrated using a variety of material compositions; Hydroxyapatite, ZnO, iron oxides, yttrium oxyhydroxide, yttrium oxide and the binary oxide series Ce-Zn. Where each material composition was used to probe different aspect of the continuous hydrothermal process reported in this work. In summary, the CHFS process has been evaluated and developed to allow for synthesis of a wide range of nanoparticle compositions with different particle properties. Process modifications have been evaluated and shown to be suitable for the synthesis of target materials.

Continuous flow reaction using micro-reactors is a valued technology due to its excellent mass and heat transfer performance, reduced reactor volume, handling capacity of hazardous reactions, and many other process intensifications. These intensifications opportunities interest the fine chemicals, pharmaceuticals producers and other multiphase reaction users who currently use batch processes or already use continuous flow. In this thesis, elements of passive and active mixing are investigated for the application of immiscible liquid-liquid systems. In the first study, the effects of geometrical arrangements of a residence time between mixing units on the interphase mass transfer rates are evaluated with four different immiscible liquid-liquid systems. A presentation of an algorithm for the optimal selection of a reactor and its operating conditions is given in order to enable easy and improved use of one’s micro-reactor. In the second study, the impact of a secondary pulse flow on interphase mass transfer is investigated. A coil without internal baffles is used as the oscillatory-flow coil reactor with a continuous active mixing source. The best application for the reactor is determined using a comparison to other complementary continuous flow platforms in the toolbox approach. The novel advancements presented here will help lead new molecular discoveries and connect the laboratory science scale to the process engineering production scale.

Le furfural (FF) et le 5-hydroxyméthylfurfural (HMF) ont été identifiés comme d'importants produits chimiques polyvalents d'origine biologique. Leurs produits d'oxydation, de réduction, d'hydrolyse et de polymérisation ont suscité un grand intérêt pour leur haute valeur ajoutée et leurs vastes applications. L'objectif de ce travail de doctorat est de réaliser la conversion du FF et du HMF en produits de haute valeur en aval dans des procédés conventionnels et d'intensification. La comparaison entre le chauffage conventionnel et la méthode de chauffage par micro-ondes, par lots avec un régime d'écoulement continu a été explorée en ce qui concerne les dérivés des FF et la réaction de valorisation du HMF. Le développement de catalyseurs plus écologiques, durables et efficaces pour réaliser la conversion des composés d'origine biologique a été étudié. Des composés cibles tels que le lévulinate de méthyle (ML), la gamma-valérolactone (GVL), l'acide 5-hydroxyméthyl-2-furancarboxylique (HMFCA), l'acide 2,5-furandicarboxylique (FDCA) ont été étudiés. En même temps, l'application du FDCA a également été effectuée, la production de trois différents types de polyesters à base de furanne : le polyéthylène-2,5-furandicarboxylate (PEF), le polyhydropropyl-2,5-furandicarboxylate (PHPF) et le polydiglycérol-2,5-furandicarboxylate (PDGF) ont été réalisés par polytransestérification entre le diéthyl furane-2,5-dicarboxylate (DEFDC) et un prépolymère défini à base de diol-furanne ou de diglycérol pur. Plusieurs questions importantes ont été soulevées afin de concevoir des processus plus écologiques que les processus actuels. Par exemple, les expériences pour l'oxydation du HMF ont été réalisées dans l'eau. L'irradiation par micro-ondes a été choisie comme méthode de chauffage pour accélérer la réaction. Les réacteurs à flux continu, tels que Pheonix, H-cube Pro ainsi que les micro-ondes à flux continu ont été identifiés comme des alternatives intéressantes pour améliorer la productivité des composés cibles. En conséquence, des résultats prometteurs ont été obtenus du point de vue de l'industrie
Furfural (FF) and 5-hydroxymethylfurfural (HMF) have been identified as important bio-based versatile chemicals, their oxidation, reduction, hydrolysis and polymerization products attracted more interests for the high value and Wide applications. The aim of this PhD work is to realize the conversion of FF and HMF into high value downstream products in both conventional and intensification processes. Therefore, the comparation between conventional heating and microwave heating method, batch With continuous flow regime was explored regarding FF derivatives and HMF valorization reaction in my work. The development of greener, durable and efficient catalysts to realize the conversion of bio-based compounds has been employed. Target compounds such as methyl levulinate (ML), gamma-valerolactone (GVL), 5-hydroxymethyl-2-furancarboxylic acid (HMFCA), 2,5-furandicarboxylic acid (FDCA) were investigated. At the same time, the application of FDCA was also performed, the production of three differen kinds of furan-based polyesters: polyethylene-2,5-furandicarboxylate (PEF), polyhydropropyl-2,5furandicarboxylate (PHPF) and polydiglycerol-2,5-furandicarboxylate (PDGF) were realized through polytransesterification between diethyl furan-2,5-dicarboxylate (DEFDC) and a defined diol furan-based prepolyme or pure diglycerol. Several important issues were identified in order to design processes greener than the current ones. For instance, the experiments for HMF oxidation were performed in water. Microwave irradiation has been chosen as the heating method to accelerate the reaction. Continuous flow reactors, such as Pheonix, H-cube Pro as well as microwave continuous flow were identified as interesting alternatives to improve the productivities of target compounds. As a result, some promising results were obtained in the viewpoint of industry

碩士
國立成功大學
化學工程學系
88
In this study, tributylamine was immobilized on chloromethylated poly-styrene polymer which was utilized as a support to prepare the triphase catalysts. All of the prepared triphase catalysts were then used to catalyze the ether reaction of n-bromobutane (the organic reactant) with sodium phenolate (the aqueous reactant) for synthesizing n-butyl phenyl ether. The feasibility of carrying out this triphase catalytic reaction by employing a continuous-flow stirred vessel reactor（CFSVR）was also investigated. The dissertation is divided into three parts. The first part relates to the conditions for immobilizing tributylamine on chloromethylated polystyrene polymeric supports. The second part presents the results and discussion of triphase catalysis by the prepared triphase catalysts in a batch reactor. The third part deals with the triphase catalysis in a continuous flow stirred vessel reactor, which was designed by our laboratory, operated under the conditions determined by referring to the results obtained in the second part. In the first part, the variables including the properties of polymeric support（extent of chloromethylation, degree of crosslinking, particle size）, temperature, kinds of organic solvents and the concentration of tributylamine affecting the immobilization reaction were investigated. From the experimental results, it is found that the reaction is a limiting step in the immobilization process. Besides, high extent of chloromethylation, high reaction temperature, high molar ratio of tributylamine to chloromethyl group in supports（6:1）and aprotic solvent are beneficial to immobilization reaction rate and the amount of tributylamine immobilized on the support. In the second part, the factors influencing the conversion of n-bromobutane and the fractional yield of n-butyl phenyl ether were investi-gated. The factors include the order of solvent addition, agitation speed, volumetric ratio of organic solvent and water, the amount of catalyst, reaction temperature, the kinds of organic solvents, the concentration of reactant in organic or aqueous phase, and the kinds and amounts of salts. The experimental results show that the supported catalyst prepared from the first part has good catalytic activity for the reaction between n-bromobutane and sodium phenolate. The mass transfer resistance can be neglected when the agitation speed is beyond 200 rpm. A higher conversion of n-bromobutane can be obtained when the volumes of organic solvent and water are equal. The increases in the amount of catalyst and temperature will enhance the reaction rate, but a high concentration of reactant in organic or aqueous phase and the addition of salts lowers the conversion of n-bromobutane. However, the existence of salts benefits the fractional yield of the main product（n-butyl-phenyl-ether）. When a nonpolar solvent such as n-heptane is utilized, a higher conversion of n-bromobutane can be obtained at a sacrifice of the fractional yield of the main product. The order of solvent addition has less effect on the conversion of n-bromobutane. A triphase catalyst will have a higher catalytic activity when it is provided with an appropriate lipophilicity. In the third part, the above three-phase reaction was carried out in a continuous-flow stirred vessel reactor under the conditions determined by referring the results obtained from a batch reactor. The effects of variables, including agitation speed, catalyst deactivation, the amount of catalyst, concentrations of reactants in organic and aqueous phases, reaction temperature and the volumetric flow rate of organic and aqueous phase on the reaction were investigated. The experimental results reveal that the conversion of n-bromobutane maintains a constant value when the agitation speed is over 400 rpm. The reaction rate increases with the increasing amount of catalyst and temperature. The conversion of n-bromobutane decreases with the increase of the volumetric flow rate of the organic and aqueous phases. With the increase of the reactant concentration（n-bromobutane）in the organic phase, the conversion of n-bromobutane will at first maintain a fixed value （< 0.018mole）and then decreases. On the other hand, with the increase of the reactant concentration（sodium phenolate）in the aqueous phase, the conversion of n-bromobutane will increase first and then decreases, and an optimum value exists. As to the stability, the triphase catalyst slightly loses its activity during a long-time operation.

碩士
國立成功大學
化學工程學系
89
In this study, the feasibilities of using tri-liquid-phase and liquid-liquid-solid phase transfer catalysis techniques for synthesizing allyl phenyl ether by etherification of allyl bromide (the organic reactant) and sodium phenolate (the aqueous reactant) were evaluted and compared. Tetrabutylammonium bromide, a soluble catalyst, was used in the tri-liquid-phase catalysis while the supported tributylamine, which was immobilized on the chloromethylated styrene-DVB copolymer, was employed as the triphase catalyst. Both catalytic reactions were carried out in a continuous-flow stirred vessel reactor (CFSVR). This dissertation consists of four parts. In the first part, the experimental results of the tri-liquid phase catalysis in a CFSVR were explained and discussed. The second part deals with the liquid-liquid-solid phase transfer catalysis in a batch reactor, while the third part presents the results of the liquid-liquid-solid phase transfer catalysis in a CFSVR, which was operated under the conditions determined by referring to the results obtained in the second part. The performances of these two techniques, tri-liquid and liquid-liquid-solid phase transfer catalysis, were compared in the fourth part. In the first part, the effects of operating variables including mole fraction of QBr, inlet reactant mole ratio, agitation speed, operating temperature, reactant volumetric flow rate, stability of catalysts and the installation of baffles in the bottom of reactor on the performance of the tri-liquid phase catalytic system were investigated. Experimental results indicate that increasing the amount of salts and utilizing non-polar organic solvent will enhance the formation of third-liquid phase. To concentrate catalysts in the third-liquid phase and to save the dosage of catalysts, appropriate mole fraction of QBr should be between 0.3 and 0.5. Feed with equal organic-to-aqueous reactant molar ratio will reduce the catalyst loss rate. The interfacial mass transfer resistance can be neglected when the agitation speed is beyond 300 rpm. However, catalyst loss rate would rise up when the agitation speed exceeded 800 rpm. Therefore, agitation speed was fixed at 800 rpm in this study. The installation of baffles improves the separation of third-liquid phase and aqueous phase, hence reduce catalysts loss rate effectively. High temperatures will lower catalyst loss rate, while low temperatures reduces stability of third-liquid phase. Therefore, a high temperature is preferred, the reasonable operating temperature is 50℃. For finding proper operating conditions for the continuous operation of the liquid-liquid-solid system, in the second part, the effects of the operating variables, including agitation speed, volumetric ratio of organic solvent and water, kinds of organic solvents, amount of catalysts, operating temperature, kinds and amounts of salts, on the performance of a batch reactor were studied first. The experimental results show that: The interfacial mass transfer resistance can be neglected when the agitation speed is fixed at 600 rpm. Higher conversion of allyl bromide and fraction yield of allyl phenyl ether will be obtained when the volumes of organic solvent and water are equal. Kinds of organic solvent have little effect on the fraction yield of main product when no catalyst is used. However, organic solvent of higher polarity increases not only the conversion of allyl bromide but also the fraction yield of allyl phenyl ether when 3g of catalysts are employed. A high temperature will induce more side-reactions while a low temperature results in water solvation, appropriate temperature is 40℃. Existence of salts restrains the activity and selectivity of catalysts. The extent of inhibition depends on the amount of salts added but is nearly independent on the kinds of salts. The third part presents the results of the reaction carried out in a CFSVR under the conditions determined by referring to the results obtained in the second part. The variables investigated include agitation speed, amount of catalysts, reactant volumetric flow rate, operating temperature and catalysts deactivation. Experimental results reveal that catalyst decays obviously under high temperatures. To prevent evaporation, the proper temperature is 40℃. Increasing the amount of catalyst will give a higher reaction rate, however, excess catalysts will cause coagulation and the catalyst particles would not be well scattered in agitation. Because etherification reaction in this experiment is irreversible pseudo-first-order, increasing the inlet aqueous or organic reactant concentration will have little effect on the conversion of allyl bromide. As to the stability, catalyst obviously loses its activity during a long-time operation. The inlet dispersion phase can not mix well immediately with another dispersion phase primarily existing in the CFSVR, therefore, the observed outlet concentration of allyl bromide is higher than the predicted value. In turn, both the reaction rate and the conversion are higher than the value predicted from the model for the batch reactor. The performances of the tri-liquid-phase and liquid-liquid-solid systems are compared in the final part. The comparison is based on five items namely, activity, selectivity, stability, the operation of continuous-flow reactor and the procedure of preparing catalysts. (1). Because of the hydrophobic property of polymer-supported catalysts, the aqueous reactant is hard to diffuse into the active sites inside the catalysts, the reaction of liquid-liquid-solid catalytic system only proceeds on the external surface of catalyst particles. Therefore, the catalytic activity in the tri-liquid phase catalysis is much better than that in the liquid-liquid-solid phase transfer catalysis under the same amount of catalysts. (2). The third-liquid phase is more stable than the polymer-supported catalyst, but the third-liquid phase might be dissolved slightly in the water. (3). The fraction yield of main product obtained by the tri-liquid phase transfer catalysis is higher than that with the liquid-liquid-solid phase transfer catalysis. Oxygen-allylation is the main reaction in the tri-liquid phase catalysis. However, side-reactions may take place in carbon-allylation pathway within liquid-liquid-solid phase transfer catalysis. (4). Both of tri-liquid and liquid-liquid-solid phase transfer catalysis can recover catalysts easily but excessive concentration of salts in the tri-liquid phase catalytic system may result in the formation of salt crystals and the loss of catalysts. (5). The procedure of preparing polymer-supported catalysts is complicated and the reproducibility is not as well as the formation of a third liquid phase in the tri-liquid phase system. 1-1 傳統的兩液相反應系統---------------------------------------------------1 1-2 相間轉移觸媒的種類------------------------------------------------------2 1-3 液-液-固三相催化反應----------------------------------------------------4 1-3-1 液-液-固三相觸媒-------------------------------------------------4 1-3-2 續流式液-液-固三相催化反應----------------------------------6 1-4 三液相催化反應------------------------------------------------------------7 1-4-1 三液相催化反應系統---------------------------------------------7 1-4-2 第三液相觸媒的重複使用性------------------------------------8 1-5丙烯基苯基醚的合成-------------------------------------------------------8 1-6本論文的研究內容--------------------------------------------------------10 第二章 實驗--------------------------------------------------------------------------12 2-1 實驗藥品-------------------------------------------------------------------12 2-2 實驗方法-------------------------------------------------------------------13 2-3 分析方法-------------------------------------------------------------------16 2-3-1 固體觸媒中氯離子含量（活性基）之分析---------------------16 2-3-2 四正丁基銨離子濃度的分析------------------------------------18 2-3-3 氣相層析法（G.C.）分析-------------------------------------------18 2-4 校正曲線-------------------------------------------------------------------19 2-5 反應物轉化率與主產物生成分率的定義----------------------------20 第三章 續流式三液相反應--------------------------------------------------------25 3-1 形成第三液相之適當條件--------------------------------------27 3-2 適當操作條件之分析-------------------------------------------29 3-3 不同流率下反應器所需穩定時間-------------------------------29 3-4擋板效應對轉化率與觸媒流失率的影響-----------------------30 3-5 攪拌速率的效應--------------------------------------------------------30 3-6反應溫度與進料流率的效應------------------------------------------31 3-7 不同莫耳比進料的效應-------------------------------------------32 3-8 三液相觸媒的穩定性-------------------------------------------------33 第四章 批式液-液-固三相反應---------------------------------------------------44 4-1攪拌速率對反應的影響--------------------------------------------------46 4-2 油、水體積比對反應的影響---------------------------------------------47 4-3 有機溶劑種類對反應的影響-------------------------------------------48 4-4 觸媒添加量對反應的影響----------------------------------------------49 4-5 溫度對反應的影響-------------------------------------------------------50 4-6 丙烯基溴添加量對反應的影響----------------------------------------51 4-7 酚化鈉添加量對反應的影響-------------------------------------------51 4-8鹽類種類與添加量對反應的影響--------------------------------------52 4-9 觸媒重複使用次數對反應的影響-------------------------------------53 4-10 機械攪拌力對觸媒活性的影響---------------------------------------53 4-11 反應速率式的推導-----------------------------------------------------54 第五章 續流式液-液-固三相反應------------------------------------------------75 5-1不同流率下反應器所需穩定時間--------------------------------------75 5-2 攪拌速率的效應----------------------------------------------------------76 5-3 觸媒添加量的效應-------------------------------------------------------76 5-4 反應溫度與進料流率的效應-------------------------------------------77 5-5 三相觸媒的穩定性-------------------------------------------------------77 5-6 酚化鈉濃度效應----------------------------------------------------------78 5-7 丙烯基溴濃度效應-------------------------------------------------------78 5-8 由續流攪拌式反應器推測反應速率式-------------------------------78 5-9續流攪拌式反應器與批式反應器的比較-----------------------------79 第六章 結論與未來研究方向-----------------------------------------------------91 6-1 三液相系統與液-液-固系統之綜合比較-----------------------------91 6-1-1催化活性------------------------------------------------------------91 6-1-2觸媒穩定性---------------------------------------------------------91 6-1-3反應選擇性---------------------------------------------------------92 6-1-4續流式操作的難易度---------------------------------------------93 6-1-5觸媒製備程序------------------------------------------------------93 6-2 結論-------------------------------------------------------------------------93 6-3 對未來研究方向建議----------------------------------------------------97 參考文獻-----------------------------------------------------------------------------100 自述-----------------------------------------------------------------------------------104

碩士
國立成功大學
化學工程學系
84
ABTRACT In a previous study in our laboratory on the reaction between n-butyl bromide (BuBr) and sodium phenolate (NaOPh) with tetrabutylammonium bromide (QBr) as a phase transfer catalyst,we found that a third liquid phase appeared when the aqueous and organic phases with poor catalyst. The reaction rate in such a tri-liquid-phase phase transfer catalysis is faster than the bi-liquid-phase system,and the catalyst can be easily recovered and reused.In this work we try to find the optimal operating conditions for the same reaction in batch and continuous-flow reactors. The experimental results reveal that the reaction rate increases with the amount of QBr. When lesser amount of NaOPh is used,the reaction rate will increase first and then decrease with the addition of NaOH,until it becomes a stale condition.Thougt lift up the reaction temperature will be helpful about the reaction,the catalyst is more easily decomposed. The results of continuous-flow reactor show that the concertration of catalyst,and the conversion of BuBr in turn,will decline slowly with the operation time though the solubilities of catalyst in aqueous and organic solutions are small.This weakness can be overcome by adding a small amount of catalyst in aqueous feed. In the investigation on the main factors affecting the reaction rate,we found that low concertration of NaOPh,and high concertration of QBr and NaOH would benetic the generation of a third liquid phase.Under these operating conditions,high conversion of BuBr can be achieved in less reaction time when a batch reactor is employed,it is also applied to the operation of a continuous-flow reactor. From this study,we can understand more about the optimal operating conditions for the phase transfer catalysis reaction in batch and continuous-flow reactors.